1. Field of the Invention
This invention relates to a camera module and its manufacturing method, specifically to a small size camera module suitable to be incorporated into a portable device such as a mobile phone and a manufacturing method of it.
2. Description of the Related Art
A mobile phone with camera function has come into widespread use in recent years. This type of mobile phone incorporates a small size camera module. FIG. 11 is a cross-sectional view showing a structure of such a camera module.
FIG. 11 shows a lens-barrel 50, a lens 51 mounted inside the lens-barrel 50 and an IR filter 52 to block infrared radiation attached to a mouth of the lens-barrel 50. It also shows an image sensor chip 60 housed in a space within the lens-barrel 50 and electrically connected with a printed circuit board 70.
The image sensor chip 60 converts light incident on it from a photogenic subject through the IR filter 52 and the lens 51 into electric signals. In the image sensor chip 60, CCDs (Charge Coupled Devices) are formed in a surface of a silicon chip 61 and a supporting glass substrate 62 is bonded to the silicon chip 61 to bolster it.
Each of redistribution wirings 64A and 64B is formed extending from each of electrode pads 63A and 63B, which are formed on a peripheral surface of the image sensor chip 60, over a side surface and to a back surface of the silicon chip 61.
Each of the redistribution wirings 64A and 64B extends onto a glass substrate 65 which is bonded to the back surface of the silicon chip 61. Each of bump electrodes 66A and 66B is formed on an end of each of the redistribution wirings 64A and 64B extended onto the glass substrate 65. The bump electrodes 66A and 66B are connected to the printed circuit board 70.
A DSP (Digital Signal Processor) 80, which performs video signal processing on the electric signals from the image sensor chip 60, is connected to a back surface of the printed circuit board 70 through bump electrodes 81A and 81B.
In the camera module described above, the lens-barrel 50, the lens 51, the IR filter 52 and the image sensor chip 60 are discrete components, and the camera module is assembled by putting these discrete components together. This causes difficulty in reducing the size and manufacturing cost of the camera module.